Narrative:

After departing lax, we contacted so cal departure. We were asked if we had company in sight. We did. The controller advised us to maintain visual separation and advised company that a brasilia would be climbing above them from their 6 O'clock position. We were cleared to 6000 ft MSL. I advised the first officer, who was flying, that we would have to increase our climb rate. He complied. When we leveled off at 6000 ft, our airspeed increased rapidly to 230 KIAS. I had the company aircraft in sight at about 11 O'clock low. We were proceeding to vtu as cleared. The first officer called for cruise power which I set. When I looked up the first officer asked me if I still had the aircraft in sight. I located the aircraft just as it was about to pass under the nose. Since its position lights were backgnded by the black ocean, I could not tell exactly how close we came to the other aircraft, but I thought we had at least 1000 ft clearance. Perhaps I had thought this because of the advisory that the controller had made to our traffic about us passing overhead, but I had never verified what altitude our traffic was climbing to. After we passed, the crew of the metroliner came on the frequency and said 'not funny guys.' I did not know that comment was for us until the crew asked ATC for the flight number of the brasilia that just passed. I then answered with our flight number and said that I was on company frequency. I spoke to the crew and explained that we thought they were 1000 ft below. I did not know how close we had come to the other aircraft until the following evening when the first officer of our aircraft spoke to the captain of the other aircraft who said that we passed within 200 ft of their aircraft. If our aircraft had been equipped with TCASII, then the aural warning would have gotten my attention back outside from setting cruise power quickly. I also should have verified with the controller what altitude our traffic was climbing to. We were both on IFR flight plans in VFR night conditions. It was pitch black out there and a couple of blinking red lights are not the best way to judge closure rates. Callback conversation with reporter revealed the following information: the reporting aircraft was cleared to 6000 ft. Both reporting pilots believed that the other aircraft was cleared only to 5000 ft, when in actuality it was cleared to 9000 ft. The reporting captain was watching the other aircraft all of the time and does not believe that her aircraft came 'that close' to the other aircraft. The first officer of the other aircraft made an irregularity report to his air carrier complaining of the air traffic situation. The air carrier has contacted ZLA about this situation. The reporting captain believes that ZLA and lax tower are now more careful when launching a brasilia behind a metroliner because of the difference in performance, both climb and cruise. Supplemental information from acn 272831: relative speed difference between our aircraft (estimated 50-75 KTS). We both agreed there was at least 1000 ft vertical and some lateral separation. Even with legal separation, when we passed them from behind and to the side it probably startled them. We had our landing lights, strobes and position lights on, so we probably appeared closer than we actually were. Supplemental information from acn 273595: we were cleared direct vtu climb to 9000 ft. Climbing through 5500 ft, the copilot exclaimed, 'what the hell!' I looked up to see a same air carrier brazilia pass over the top of us at no more than 200 ft above us, same direction. We asked the controller for the flight number, they gave us X. Evidently, flight X was behind us and requested to maintain visual separation with us so they could pass us. They leveled at 6000 ft direct vtu, we were climbing through 5500 ft for 9000 ft also direct ventura and got dangerously close to us.

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Original NASA ASRS Text

Title: 2 ACR LTTS MAY HAVE HAD A CONFLICT.

Narrative: AFTER DEPARTING LAX, WE CONTACTED SO CAL DEP. WE WERE ASKED IF WE HAD COMPANY IN SIGHT. WE DID. THE CTLR ADVISED US TO MAINTAIN VISUAL SEPARATION AND ADVISED COMPANY THAT A BRASILIA WOULD BE CLBING ABOVE THEM FROM THEIR 6 O'CLOCK POS. WE WERE CLRED TO 6000 FT MSL. I ADVISED THE FO, WHO WAS FLYING, THAT WE WOULD HAVE TO INCREASE OUR CLB RATE. HE COMPLIED. WHEN WE LEVELED OFF AT 6000 FT, OUR AIRSPD INCREASED RAPIDLY TO 230 KIAS. I HAD THE COMPANY ACFT IN SIGHT AT ABOUT 11 O'CLOCK LOW. WE WERE PROCEEDING TO VTU AS CLRED. THE FO CALLED FOR CRUISE PWR WHICH I SET. WHEN I LOOKED UP THE FO ASKED ME IF I STILL HAD THE ACFT IN SIGHT. I LOCATED THE ACFT JUST AS IT WAS ABOUT TO PASS UNDER THE NOSE. SINCE ITS POS LIGHTS WERE BACKGNDED BY THE BLACK OCEAN, I COULD NOT TELL EXACTLY HOW CLOSE WE CAME TO THE OTHER ACFT, BUT I THOUGHT WE HAD AT LEAST 1000 FT CLRNC. PERHAPS I HAD THOUGHT THIS BECAUSE OF THE ADVISORY THAT THE CTLR HAD MADE TO OUR TFC ABOUT US PASSING OVERHEAD, BUT I HAD NEVER VERIFIED WHAT ALT OUR TFC WAS CLBING TO. AFTER WE PASSED, THE CREW OF THE METROLINER CAME ON THE FREQ AND SAID 'NOT FUNNY GUYS.' I DID NOT KNOW THAT COMMENT WAS FOR US UNTIL THE CREW ASKED ATC FOR THE FLT NUMBER OF THE BRASILIA THAT JUST PASSED. I THEN ANSWERED WITH OUR FLT NUMBER AND SAID THAT I WAS ON COMPANY FREQ. I SPOKE TO THE CREW AND EXPLAINED THAT WE THOUGHT THEY WERE 1000 FT BELOW. I DID NOT KNOW HOW CLOSE WE HAD COME TO THE OTHER ACFT UNTIL THE FOLLOWING EVENING WHEN THE FO OF OUR ACFT SPOKE TO THE CAPT OF THE OTHER ACFT WHO SAID THAT WE PASSED WITHIN 200 FT OF THEIR ACFT. IF OUR ACFT HAD BEEN EQUIPPED WITH TCASII, THEN THE AURAL WARNING WOULD HAVE GOTTEN MY ATTN BACK OUTSIDE FROM SETTING CRUISE PWR QUICKLY. I ALSO SHOULD HAVE VERIFIED WITH THE CTLR WHAT ALT OUR TFC WAS CLBING TO. WE WERE BOTH ON IFR FLT PLANS IN VFR NIGHT CONDITIONS. IT WAS PITCH BLACK OUT THERE AND A COUPLE OF BLINKING RED LIGHTS ARE NOT THE BEST WAY TO JUDGE CLOSURE RATES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTING ACFT WAS CLRED TO 6000 FT. BOTH RPTING PLTS BELIEVED THAT THE OTHER ACFT WAS CLRED ONLY TO 5000 FT, WHEN IN ACTUALITY IT WAS CLRED TO 9000 FT. THE RPTING CAPT WAS WATCHING THE OTHER ACFT ALL OF THE TIME AND DOES NOT BELIEVE THAT HER ACFT CAME 'THAT CLOSE' TO THE OTHER ACFT. THE FO OF THE OTHER ACFT MADE AN IRREGULARITY RPT TO HIS ACR COMPLAINING OF THE AIR TFC SIT. THE ACR HAS CONTACTED ZLA ABOUT THIS SIT. THE RPTING CAPT BELIEVES THAT ZLA AND LAX TWR ARE NOW MORE CAREFUL WHEN LAUNCHING A BRASILIA BEHIND A METROLINER BECAUSE OF THE DIFFERENCE IN PERFORMANCE, BOTH CLB AND CRUISE. SUPPLEMENTAL INFO FROM ACN 272831: RELATIVE SPD DIFFERENCE BTWN OUR ACFT (ESTIMATED 50-75 KTS). WE BOTH AGREED THERE WAS AT LEAST 1000 FT VERT AND SOME LATERAL SEPARATION. EVEN WITH LEGAL SEPARATION, WHEN WE PASSED THEM FROM BEHIND AND TO THE SIDE IT PROBABLY STARTLED THEM. WE HAD OUR LNDG LIGHTS, STROBES AND POS LIGHTS ON, SO WE PROBABLY APPEARED CLOSER THAN WE ACTUALLY WERE. SUPPLEMENTAL INFO FROM ACN 273595: WE WERE CLRED DIRECT VTU CLB TO 9000 FT. CLBING THROUGH 5500 FT, THE COPLT EXCLAIMED, 'WHAT THE HELL!' I LOOKED UP TO SEE A SAME ACR BRAZILIA PASS OVER THE TOP OF US AT NO MORE THAN 200 FT ABOVE US, SAME DIRECTION. WE ASKED THE CTLR FOR THE FLT NUMBER, THEY GAVE US X. EVIDENTLY, FLT X WAS BEHIND US AND REQUESTED TO MAINTAIN VISUAL SEPARATION WITH US SO THEY COULD PASS US. THEY LEVELED AT 6000 FT DIRECT VTU, WE WERE CLBING THROUGH 5500 FT FOR 9000 FT ALSO DIRECT VENTURA AND GOT DANGEROUSLY CLOSE TO US.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.